Ibasso D6 vs Practical Devices XM6

I haven't read any thing on the D6 in comparision to the Practical Devices XM6. I'm looking to get a Headphone amp/USB DAC and it broils down to the D6 vs the XM6 http://www.practicaldevices.com/amps.htm Has anybody got any opinion on the differences between these 2 products, I'm leaning toward the XM6 but the D6 is a little less money. Has anybody tried out these two headphone amp/DAC's side by side? What do you think is the better. The D6 has 2 Wolfson 8740 DAC's but is that going to get me better performance and sound quality. The XM6 has more upgrade options and a 3 year warranty and it is MADE IN THE USA or Canada. Please let me know what your opinion is and what product would you choose between the two. Your prompt replies will be appreciated.